Tubular member



March 1 8, 1930.

E. B. CARNS TUBULAR MEMBER Filed May 18, 1927 Patented Mar. 18, 1930 UNITED STATES PATENT OFFICE EDMUND B. CAIRNS, OF NEW YORK, N. Y., ASSIGNOR TO CAIRNS DEVELOPMENT COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE TUBULAR MEMBER Application filed May 18, 1927. Serial No. 192,245.

My invention relates to improvements in tubular members which can be made from sheet stock and which have a great variety of uses. The invention is intended to produce an inexpensive, light and durable memher having great strength in proportion to its weight, and constructed in such a way that it can be very easily made.

In its preferred form, the invention is triangular in cross section and tapering. It is also tubular and is made of a blank which can be scored and folded to the desired tubular shape, and with two of its sides overlapping, and secured together in a simple but unusually strong manner.- The invention can be made of sheet stock of any suitable kind, and for most purposes would be made ofsheet metal which can be scored so as to have other cross sectional shapes than trizo angular, but the triangular shape is preferable as this form of structure is exceedingly strong and can be readily made.

The invention is further intended to produce a structure or member of this kind which can be lightened by perforations through the shell and in which the production of these holes can be made to afford a strong and cheap means of fastening the overlapping parts of this structure together.

'30 Reference is to be had to the accompanying drawings in which similar reference characters represent the corresponding parts in all views.

Figure 1 is a development of the blank used in forming a triangular member.

Figure 2 is a longitudinal section on the line 22 of Figure 1.

Figure 3 is a longitudinal section on the line 33 of Figure 1.

Figure 4 is a perspective of the formed tubular member, and

Figure 5 is a cross section thereof.

The blank 10 is tapered, being relatively wide at one end and narrower at the other, and obviously this narrower part may be carried to a point, but for most purposes it is not extended so far so that the formed memher will represent a frustum of a pyramid.

The blank is preferably scored to form the longitudinal facets or sides 11, 12, 13 and 14, the'latter two being adapted to overlap as the drawing shows. Generally the meeting parts of the several facets or sides would be scored to facilitate bending, but this is not necessary, in-some cases, the essential thing being to fold the blank lengthwise to form the triangular member. The side or facet 13 is lightened by perforations 15, and the side or facet 14 which overlaps the part 13 when the blank is folded up is also pro- 50 vided with perforations 16. The perforations of the two parts 13 and 14 are adapted to register, and the perforations 15 are slight ly larger than the perforations 16, the latter being formed with flanges 17 which can be 5 readily produced by punching out the material of the sheet, and these flanges are of a length to extend through the perforations or holes 15, and to permit clinching or doubling over eyelet fashion as at 18, and thus the overlapping parts 13 and 1 1 are held together in a very strong and simple manner. It will be apparent that the tapering of the tubular member can be of any pitch desired, and it will be understood that it may be of other cross section without departing from the principle of the invention. but the triangular shape is for almost all purposes the desirable shape. It will also be understood that the several sides of the member or structure can be lightened by perforations if desired.

From the foregoing description, it will be seen that I have shown and described a tubular member which is light, strong and cheap, 5 and can have a very great variety of uses. It can be used for longrons, spars, struts, braces, and other parts of air craft construction. It can be used in the making of boats or other structures; can be used for building purposes; is well adapted for use as a telephone or telegraph pole or flagstaff, and in fact its application to many structures will beevident. v

I claim:

1. A. tubular member formed of a one piece tapering blank folded to triangular cross section with two overlapping sides substantially equal in width the inner of which has its terminal edge fitting in a corner of said tubu- 100 lar member, said overlapping sides having registering holes with flanges around one set of holes extending through the other set of holes and clinched to fasten the sides together.

2. As an improved structure, a tapering tubular, fiat-sided, one piece member substantially triangular in cross section, said member having one of its sides formed of over-lapping sheet members substantially equal in width and over-lapping substan tially throughout their entire width, one of said sheet members having holes therein and the other of said sheet members having perforations with bordering flanges extending through the holes of the first member and clinching upon the said first member.

3. As an improved structure, a tapering, tubular, flat-sided, one piece member, said member havin one of its sides formed of over-lapping Sheet members substantially equal in w1dth and over-lapping substantially throughout their entire width, one of said sheet members having holes therein and the other of said sheet members having perforations with bordering flanges extending through the holes of the first member and clinching upon the said first member.

4:. As an im roved structure, a uniformly tapering, tubular, flat-sided, one piece member tri-angular in cross section, having one of its sides formed of over-lapping sheet metal sections substantially equal in width and over-lapping throughout the major portion of their width, one ofsaid sections having holes therein which are of a diameter slightly less than the width of the section in which they are formed, the other of said sheet members having erforations with bordering flanges exten ing through the holes of the first member and clinching upon the said first member.

5. As an improved structure, a uniformly tapering, tubu ar, flat-sided, one piece memher having one of its sides formed of overlapping sheet metal sections substantially equal in width and over-lapping throughout the major portion of their width, one of said sect ons having holes therein which are of a diameter slightly less than the Width of the section in which they are formed, the other of said sheet members having perforations with bordering flanges extending through the holes of the first member and clinching upon the said first member.

In testimony whereof, I have signed my name to this specification this 13th day of May, 1927.

EDMUND B. CARNS. 

